Rotational-optical model and the similar channels effect

Abstract

It is shown that the structure of the deformed real and imaginary parts of the phenomenological optical (OMPP) for rotational nuclei can be understood from a microscopic point of view. We point out that some channels that differ only in the rotational state of the target are rather similar in structure. The consequences of this similarity as regards the imaginary part of the microscopic optical matrix potential (OMP rn) for low energies (few MeV or less), the average direct and compound crosssections, the validity of the Hauser-Feshbach formalism and the experiment are investigated.The deformed OMP p have been successfully used in the analyses of inelastic nucleon scattering data by rotational nuclei. Recently a microscopic approach for inelastic nucleon scattering by deformed nuclei has been formulated [I] in the spirit of a continuum shell-model [2]. A microscopic optical matrix potential (OMP m) can be constructed [3] in the space of those channels {X~} which involve the target in a rotational state of the ground state band using the representation {X~, ~}. A channel state X~ describes the situation in which an asymptotically non-vanishing occupied single-particle state is coupled to a target state. The states {~} on the other hand, describe the case when all nucleons occupy single particle orbitals bound in the Hartree-Fock field of the target nucleus. The states {~} are called the bound states embedded in the continuum (BSEC). The BSEC are needed to describe the compound scattering. The states {X~, ~} are fully antisymmetric in A nucleon coordinates and have good total angular momentum J. In Sect. I the real parts of the OMP p and OMP m are compared, Sect. II gives the comparison for the imaginary parts at low energies where we introduce the similar-channelseffect (SCE) and in Sect. III the consequences of the correlations of partial width amplitudes due to the SCE are studied. I. Comparison of Real Deformed Terms of OMP p and OMP mThe widely used OMP p prescription relates the real parts of the inelastic form factors to the ground state elastic form factor. We want to 15 Z. Playsik, Bd. 262